So I've been tinkering more and more with scripts lately, learning tidbits of knowledge here and there, and I was wanting to create a script to install a program (MyDefrag), but I keep getting stuck trying to include everything I need to for the program. I tried using the program I already had installed on my PC, but it was a x64 version and I am using a x86 version of Win7PESE. A workaround that I found for it was to just include the installer as an executable on the desktop and install it once the PE loads, but I figured that there had to be a more efficient way of doing this, like a way that WinBuilder could install the program for me. My current method that I found online was a way to initiate the executable during the boot of the PE, but once again, I was just wanting to have it already installed. Steps in the right direction are very much appreciated. 
Here is what I have right now (This is of course excluding the executable after it has been decompressed into the .script file):
[main] Title=MyDefrag Description=(v4.3.1)MyDefrag is a disk defragmenter and optimizer (a maintenance utility to make your harddisk faster) for Windows 2000, 2003, XP, Vista, 2008, Win7, and for X64. Level=5 Version=1 Selected=True [variables] %ProgramTitle%=MyDefrag %ProgramEXE%=MyDefrag-v4.3.1.exe %ProgramFolder%="MyDefrag" [process] unpack AddAutoRun,"MyDefrag","%PE_Programs%\%ProgramFolder%\%ProgramEXE%","/install"